Drying apparatus



June 16, 1942:. M. E. HANSON DRYING APPARATUS Filed Feb. 2, 1940 1.? |||1\ g air Arroezvey Patented June 16, 1942 v I H, which walls form a UNITED STATES .PATENT OFFICE Milton a. Hanson, Haddonileld, N.

1., asslgnor to Mass.

B. F. Sturtevant Company, Boston, Application February 2, 1940, Serial N6. 316,898

(Cl. s4 -1co) 2 Claims.

This invention relates to drying apparatus and relates more particularly to dryers using heated air for drying web material such as'paper, cloth, and the like or fonthe drying of printing or coatings on the surface oi. same.

This invention provides a compact, eillcient dryer providing the air heater and a centrifugal fan for moving air over same, inside a single insulating casing. which also houses drying nozzles and recirculated air passages. This design of dryer has been found particularly suitable for use with small paper printing machines. the space required being much less than required by prior dryers having fans and heaters mounted on the exterior of the dryer casings.

An object of the invention is to increase the efllciency of, and to reduce the space required by.

web dryers.

Other objects of the invention will be apparent from the following description and from the drawing. I

The invention will now be described with reference to the drawing, of which:

Fig. 1 is a side elevation, with a portion in section and a portion in dotted outline, of one embodiment of a dryer according to this invention;

Fig. 2 is a sectional view along the lines 2-2 of Fig. 1, and

Fig. 3 is an enlarged section along the lines 33 of Fig. 2.

The dryer unit S'has the heat insulating casing 6 completely enclosing same. Mounted centrally in one end of the unit is the centrifugal fan l with the two oppositely disposed axial inlets I. The outlet 9 of the fan is connected to the two upper diverging walls l and II which extend to the ends of the'unit, and to the side walls diverging air plenum chamber l2.

The dryer nozzles i3 extend'horizontally cross wise the lower end of the chamber l2 and discharge air downwardly upon the moving web II which it is the purpose to dry. The fined heater tubes l extend crosswise the chamber I5 just above the nozzles 13, and are adapted to be supplied with steam for heating the air blown by the fan 1 through the nozzles".

The plates l6 extend vertically between ad-' jacent nozzles l3 to points adjacent the'web M and perform the functions of scraping. oi! the film of air which tends to adhere to the web I! and to leave the dryer with same; of providing turbulence in air flow thus expediting the dryof the air by guiding it crosswise the web'so that no one part drys before another, all of which result in adding to the efllciency and com-' pactness of the dryer bycutting down air and heat losses and decreasing the number of nozzles required.

The air from the nozzles 13 after leaving the web, is recirculated from both transverse sides of the web into the two fan inlets 8 as indicated through the inlet II, and recirculated air through the space between the walls of the plenum chamber. ii, the walls 6. and the fan easing, into the inlets I, and forces the mixed fresh and recirculated air through the plenum chamber [2, 'over the heater tubes i5, and through the nozzles ll upon the surface of the web It. Exhaust air flows through the outlet it into the atmosphere. While one embodiment of the invention has been described for the purpose of illustration, it should be understood that the invention is not limited to the exact apparatus and arrangement of apparatus illustrated as changes therefrom may-be made by those skilled in the art without departure from the essence of the invention.

What is claimed is: 11 A dryer for web material comprising a casing having an inlet for fresh air, an outlet for moist air, and means for moving a web to. be

- dried therethrough; comprising-a plurality of ject air-over the entire surface of a web moving therethrough; an air heater extending crosswise said casing above and substantially in alignment with said nozzles; 'a centrifuga1 fan above said heater and nozzles, said fan having axial inlets at opposite side walls of said casing and having a downwardly directed outlet, and means including diverging walls forming a plenum ing action, and of equalizing the drying effect chamber connecting said outlet of said fan with opposite endwalls of said casing, said plenum chamber having side walls spaced substantial distances from said side walls of said casing and forming passages for the air recirculated from said nozzles to said inlets ofv said fan, said heater extending substantially completely across the outlet of said chamber.

2. A dryer for web material comprising a casing having an inlet for fresh air, an outlet for moist air, and means for moving a web to be dried therethrough; comprising a plurality of aligned air nozzles spaced longitudinally of said casing and extending substantially the full length thereof; each nozzle extending a substantial distance cross-wise said casing so as to project air over the entire surface of a web moving therethrough; an air heater extending cross-wise and lengthwise said casing above and substantially in alignment with said nozzles; a

centrifugal fan at one end of said casing above 0 said heater and nozzles, said tan having axial inlet at opposite side walls of said casing and having a downwardly directed outlet; means including diverging walls forming a plenum chamber connecting said outlet of said fan with opposite end walls or said casing, said plenum chamber having side walls spaced substantial distances from said side walls of said casing and forming passages for the air recirculated'from said nozzles to said inlets of said i'an, said heater and said nozzles extending substantially completely across the outlet of said chamber, and means forming partitions between adjacent nozzles and extending below same and connecting with said passage for scraping off the film of air tending to leave the dryer with the web being dried, and for'guiding the air from said nozzles with the air scraped off said web, into said passages for recirculation.

MILTON E. HANSON. 

